The invention relates to immunological adjuvants. In particular, the invention relates to adjuvants which comprise an oil-in-water emulsion and a surfactant. Adjuvants of the invention are useful in a variety of vaccine formulations, including vaccines comprising bacterial or viral components.
The generation of immunity to infectious organisms is a powerful tool in disease control. Those antigens that induce immunity to infection are known as immunogens. The protective antibody they induce may collaborate with other natural defenses to inhibit the infective process, or they may neutralize harmful products of the infective organism such as toxins.
An effective means of enhancing the antibody response is the use of an adjuvant. Thus, an adjuvant is included in a vaccine as an additive or vehicle to enhance the response to the antigen. An adjuvant may function by different mechanisms, including (1) trapping the antigen in the body to cause a slow release, (2) attracting cells of the immune system to the injection site, (3) stimulating cells of the immune system to proliferate and to become activated, and (4) improving antigen dispersion in the recipient""s body.
A number of agents with diverse chemical properties have been used as adjuvants, including water-in-oil and oil-in-water emulsions, mineral salts, polynucleotides and natural substances. One adjuvant, known under the trademark AMPHIGEN(trademark), is described in U.S. Pat. No. 5,084,269. AMPHIGEN(trademark) adjuvant consists of de-oiled lecithin dissolved in an oil, usually light liquid paraffin. In vaccine preparations AMPHIGEN(trademark) is dispersed in an aqueous solution or suspension of the immunizing antigen as an oil-in-water emulsion.
Problems were observed when using an AMPHIGEN(trademark) adjuvant according to U.S. Pat. No. 5,084,269, above. For example, the lecithin in the AMPHIGEN(trademark) does not suffice to produce a stable emulsion of the oil, thus leading to a pool or depot of oil in the injected tissues. Mineral oil can not be metabolized or removed by the animal. As a result, the oil becomes a source of severe chronic inflammation and scarring. Emulsifying the AMPHIGEN(trademark) directly in the antigenic preparation carries the risk of damaging the antigen. Also, if the desired emulsion fails to form, the valuable antigen must be discarded.
An adjuvant useful in vaccines for animals, including humans, that is effective and solves the above problems would therefore be highly desirable.
The invention relates to an adjuvant useful for the enhancement of the immune response of an animal to an antigen. In particular, the invention relates to an adjuvant that is capable of forming an oil-in-water emulsion in a vaccine composition. The invention also relates to an adjuvant that, when used in a vaccine formulation, causes minimal inflammation and scarring at the vaccination site. The invention further relates to a vaccine formulation that contains an adjuvant of the invention. Finally, the invention relates to a method of using an adjuvant of the invention in a vaccination.
In one embodiment, the adjuvant of the invention comprises a lecithin, an oil and an amphiphilic surfactant capable of emulsifying the adjuvant, for example, a Tween or a Span surfactant. In another preferred aspect, the surfactant is Tween 80, Tween 85, Span 80 or Span 85.
In another embodiment, the adjuvant of the invention comprises a lecithin, an oil and two amphiphilic surfactants capable of emulsifying the adjuvant or a vaccine composition that contains the adjuvant. In a preferred aspect, one of the two surfactants is predominantly found in the aqueous phase, for example, Tween 80, and the other surfactant is predominantly found in the oil phase, for example, Span 80.
A lecithin is a phosphatide. Crude preparations of lecithin may include triglycerides. For purposes of the present invention, xe2x80x9clecithinxe2x80x9d encompasses both purified and crude preparations. In a preferred aspect, the lecithin is de-oiled.
Suitable oils include a mineral oil, for example, DRAKEOL(trademark) light mineral oil.
In a further embodiment, the adjuvant of the invention contains an aqueous carrier solution, for example, a physiologically acceptable buffer, water or a saline solution.
In a preferred embodiment, the adjuvant of the invention contains a lecithin, a mineral oil, two amphiphilic surfactants and an aqueous carrier solution (e.g., saline).
In another embodiment of the invention, a method to inactivate a culture of Bordetella bronchiseptica (xe2x80x9cB. bronchisepticaxe2x80x9d) using formalin and glutaraldehyde is described. In another aspect, a culture of B. bronchiseptica is provided that was inactivated using formalin and glutaraldehyde. In yet another aspect, an antigen composition from a B. bronchiseptica culture is provided that was inactivated using formalin and glutaraldehyde. In yet another aspect, a vaccine composition is provided that contains an antigen composition from a B. bronchiseptica culture that was inactivated using formalin and glutaraldehyde.